Objective,2,To explore the mechanism of modified Pentongling Formula on analgesic in endometriosis （EMs） model rats based on phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt） signaling pathway.,Methods,2,The rat model of EMs was established by autologous endometrial transplantation. The EMs rats with pain behavior were chosen by the “Up ,&, Down” method and randomly divided into model group， modified Pentongling low， medium and high dose group （,n,=8）； and the sham group was set with 8 rats. The sham group and model group were given 0.9% NaCl solution enema， and each modified Pentongling group was given different doses of modified Pentongling Formula enema. After continuous enema for 4 weeks， the changes of 50% paw mechanical withdrawal threshold （50% PMWT） in rats were observed. HE staining was used to observe the pathological changes of the endometrium in rats， immunohistochemistry was used to detect the protein expression levels of PI3K and Akt in the ectopic lesion， ELISA was used to detect the concentrations of estradiol （E,2,） in the peritoneal fluid and brain-derived neurotrophic factor （BDNF） in the serum， and RT-qPCR was used to detect the mRNA expression levels of PI3K and Akt in the ectopic lesion.,Results,2,①After modeling， the 50% PMWT of rats in each modeling group significantly decreased （,P,<,0.05）. Compared with the model group， the 50% PMWT of the modified Pentongling groups significantly increased after 4 weeks administration （,P,<,0.001）. ②HE staining showed that the epithelial cells were flat， the glands significantly decreased or even disappeared， blood vessels were abundant， and there was inflammatory cell infiltration in the stroma in the endometrial tissue of the model group. Each dose of modified Pentongling could improve the pathological morphology of endometrial tissue to different degrees， and the high dose had the best effect. ③Compared with the sham group， the expression of E,2,， BDNF was up-regulated in the model group （,P,<,0.01， ,P,<,0.001）. Compared with the model group， E2 and BDNF expression was down-regulated in modified Pentongling each group （,P,<,0.05， ,P,<,0.001）. ④Compared with the sham group， ,PI3K, and ,Akt, mRNA and protein expressions in the model group was up-regulated （,P,<,0.05， ,P,<,0.01）. Compared with the model group， the Akt protein expression was down-regulated in modified Pentongling each dose group （,P,<,0.05， ,P,<,0.01）， the ,Akt, mRNA expression was down-regulated in modified Pentongling high dose group （,P,<,0.05）， and the ,PI3K, mRNA and protein expressions were down-regulated in modified Pentongling medium and high dose groups （,P,<,0.05， ,P,<,0.01）. ⑤Correlation analysis showed that the expression of E,2,， BDNF and the mRNA and protein expression of PI3K and Akt were negatively correlated with 50% PMWT.,Conclusion,2,Modified Pentongling Formula may relieve EMs pain by inhibiting E,2, to regulate PI3K/Akt signaling pathway.